Automatic brake-slack adjuster



(No Model.) 3 Sheets-Sheet- 1.

A. PITKETHLY. AUTOMATIG BRAKE SLACK ADJUSTER.

No. 564,220. Patented July 21, 1896,.

WITNESSES: INV NTU '2 4- a 4, azwwv M ATTUR Y.

TNE NORRIS PETERS co, PHOTO-LITHQ. WASHINGTON, n. 64

v Model 3 Sheets-Sheet 2.

A. PITKETHLY. AUTOMATIC BRAKE SL-AGK ADJUSTER.

No. 564,220. Patented July 21, 1896.

WITNESSES (No Model.) I 3 Sheets-Sheet 3. A. PITKETHLY.

AUTOMATIC BRAKE SLACK ADJUSTER. No. 564,220. Patented July 21, 1896.

WITNESSES: INVENTUR;

UNITED STATES PATENT QFFICE.

ALEXANDER PITKETHLY, OF BOSTON, MASSACHUSETTS, ASSIGNOR, BY DIRECT ANDMESNE ASSIGNMENTS, TO FRANCIS V. PARSONS, OF

OSTERVILLE, MASSACHUSETTS.

AUTOMATIC BRAKE-SLACK ADJUSTER.

SPECIFICATION forming part of Letters Patent No. 564,220, dated July 21,1896.

Application filed October 10,1894. Serial No. 525,522. (No model.) I

To all whom it may concern/.-

Beitknown that LALEXANDER PITKETHLY, a citizen of the United States,residing at Boston, in the county of Suffolk and Stat-e oflllassachusettsdiave invented certain new and useful Improvements inAutomatic Brake- Slack Adjusters, of which the following is aspecification.

My invention relates to automatic brakeslack adjusters designed to beused as a part of and in connection with braking apparatus as appliedto'railway-cars and the like.

The object of my invention is to provide a simple, durable, andefficient device for automatically effecting brake-slack adjustmentwithout material change being made in the leverage angularity of eitherthe dead lever or the live lever, so that as the brake-shoes are wornthe power with which they are applied to the wheels is not diminished,as would be the case if the angularity of the levers was materiallychanged in taking up or compensation for the wear of the brake-shoes.

In accordance with this invention one of the brake-operating levers,either the live or the dead lever, as may be found most convenient, isprovided with a movable support or fulcrum, which is connected to thebrakebeamto effect movement of the said beam on the forward movement ofthe brake-lever, and the said brake-lever is also connected to thebrake-beam by a sliding or adjustable connection capable of changing itsposition with relation to the brake-beam when the shoes have becomesufficiently worn, as will be described, and which adjustable connectionbecomes fixed with relation to the brake-beam on the return movement ofthe brake-operatin g lever, so that the latter on its return move mentcarries its movable fulcrum or support toward the brake-beam a distanceequal to the change of the sliding connection with relation to thebrake-beam. The movable support or fulcrum, when moved toward thebrake-beam an amount sufficient to compen: sate for or take up the wearof the brakeshoes, is locked to the brake-beam, as will be described, sothat on its next forward movement the brake-beam will move with it as ifrigidly connected thereto. These and other features of this inventionwill be pointed out in the claims at the end of this specification.

Figure 1 represents the application of one form of brake-slack adjusterembodying this invention to a car truck having outside brakes, and Fig.2 represents my invention as applied to a car-truck having insidebrakes. Figs. 3 to l1,inclusive, are enlarged views of the adjustershown in Figs. 1 and 2. Fig. 3 shows the adjuster in side elevationsecured to the brake-beam. Fig. 4 is a plan of Fig. Fig. 5 is a sideelevation of the cam-dog. Fig. 6 is a plan of Fig. 5. Fig. 7 is a planof the cam-wheel. Fig. 8 is a front view of the cam-wheel. Fig. 9 is asectional view of Fig. 7 on the line A B. Fig. 10 is a verticalsectional view of the rack-holding device. Fig. 11 is a full sectionalview on line C D of Fig. 10.

Fig. 1 illustrates the application of one form of apparatus embodying myinvention to a car-truck of an ordinary construction having outsidebrakes, and Fig. 2 illustrates the application of the apparatus shown inFig. 1 to a car-truck having inside brakes.

In Fig. 1 the apparatus is applied or operatively connected to the livelever, and in Fig. 2 the device is applied or operatively connected tothe dead lever. For the purpose of enabling my invention to be clearlyunderstood a portion of a simple and plain car-truck, which may be ofany suitable or usual construction, is represented in partial section inFigs. 1 and 2, wherein in Fig. 1 the truck is provided with thefollowing parts,

namely: the truck-bolster 21, transom 22,

wheel-beam 23, end sills 24 and 25, axles 26 and 27, wheels 28 and 29,brake-hangers 30 and 31, brake-beams 32 and 33, brake-shoes 34 and 35,dead lever 36, dead-lever guide 37, live lever 33,1ive lever guide 39,lower brakerod 40, and upper brake'rod 41. In a like manner truck 42(shown in Fig. 2) is provided with the following parts: truck-bolster43, transom 44, wheel-beam 45, end sills 46 and 47, axles 4S and 49,wheels 50 and 51, brakehangers 52 and 53, brake-beams 54 and 55,brake-shoes 56 and 57, dead lever 58, deadlever guide 59, live lever 60,lower brake-rod 61, and upper brake-rod 62.

In order to illustrate the invention in a clear and distinct manner, itis represented in the drawings as applied to the live and dead levers,they being in an upright position but it is intended that the leversshould be set in their usual slanting position.

The mode of operation of the device is substantially the same whenapplied either to outside brakes or inside brakes. Figs. 4 to 11,inclusive, are enlarged views of the device or apparatus shown in Fig. 1as applied to the live lever 38, which, in accordance with thisinvention, is provided with a fulcrumpin 66, movable in a transverseslot of a frame 03, provided with a longitudinal slot 6% substantiallyat right angles to the transverse slot 65, the frame 03 constituting asupporting-frame for the fulcrum-pin, and in practice the said frame issecured to the brake-beam 33, and in order to obtain as long abrake-lever as possible the frame 63 is secured to the brake-beam at anangle or so that the slot 61 inclines in one direction, while the slot65 inclines in a direction at right angles to the first inclination. Thefulcrumpin 66 has mounted upon it cam dogs or pawls 67 68, which, in thepresent instance, cooperate with the double segmental toothed camwheel69, mounted to turn upon the pivot-pin 70, supported by the sides of theframe 63. The segmental cam-wheel 69 is connected to the fulcrum-pin 66by means of the links 72 73, which engage the ends of a pin 7 at,secured to or forming part of the segmental wheel 69, on its rear side.

The cam-wheel 69 is composed in the present instance of the two toothedsegmental cams 75 7 6, which are united by means of the cross-piece 77,(see Figs. 7 and 8,) which crosspiece is provided with a projectingflange 78, through which the pivot pin or arbor 7 O is extended, thesaid cross-piece also having secured to or forming part of it the pin71.

In the above construction it will be seen that the segmental cam-wheel69 is secured to the frame 63 by the pivot-pin 70, and that by means ofthe pin 7 1 and the links 72 73 the segmental wheel 69 is connected tothe f ulcrum-pin 66, and when the brake-shoes are not worn the segmentalcam-wheel 69 and the dogs 67 68 form, practically, a rigid connectionbetween the brake-operating lever 38 and the frame (33, and consequentlyeffect, practically, a rigid connection between the brake-operatinglever 38 and the brake-beam 33, so that when the brake-lever 38 is movedforward or toward the left (viewing Fig. 3) the brake-beam 33 will bemoved with it, the lever 38 turning on the pin 66 as a fulcrum. Thecam-dog 67 (shown separately in Figs. 5 and 6) is provided with teeth,as herein shown, which engage the teeth of the cam-wheel GS), and thesaid cam-dog is provided with a hole to receive the fulcrum-pin and witha side lug 81, which is adapted to slide in one of the transverse slots65 in the supportingframe, the lug being made, for the best results, ofa less width than the slot, so that the dog will readily engage thecam-wheel. The dogs or pawls 67 68 are of like construction, except thatthey are made right and left as regards the location of the side lug 81.The brake-lever 38 has connected to its short arm, below thesupporting-frame 63, a toothed rack-bar 71, pivotally connected at oneend to the short arm of the lever 38 and having its other end adjustablyconnected, as will be described, to the brake-beam.

I11 the present instance the toothed end of the rack-bar 71 is extendedthrough a housing 82, secured to the brake-beam 33, as shown in Figs. 1,3, and 4, while in Fig. 2 the housing 82 is shown as secured to theframe 63.

Referring to Figs. 10 and 11, the housing 82 is shown as containingwithin it a toothed rack dog or pawl 83, designed to engage the teeth ofthe rack-bar 71, the dog 83 being held in its housing by the set-screw84, by means of which the horizontal play of the dog in its housing maybe easily regulated. The dog 83 is held in engagement with the rack-bar71 by means of the spring 85, which, as herein shown, is placed betweenthe dog and the handle 86, to which the dog is loosely secured by meansof the screw 87. The handle 86 is pivoted on the pin 88, extendedthrough the housing, and is held in a fixed position by means of theretaining-pin 89, by the withdrawal of which thehandle and itsadjustments, including the dog, may be readily lifted, thereby releasingthe toothed rack-bar 71 and permitting the ready hand adjustment of thebrake apparatus, especially when it is first applied.

By means of the rack-bar 71 and the toothed. dog 83 it will be seen thatthe short arm of the brake-operating lever 38 is connected to thebrake-beam 33. The operation of the apparatus as applied to outsidebrakes, and as shown in Fig. 1, may be readily understood from aninspection of Figs. 1 and 3,

wherein the brake apparatus is represented in its correct workingposition, the brakeshoes being at their proper distance from the wheels.

By the application of brake power to the upper brake-rod the brakes maybe applied in the usual manner, the direction of movement of thedifferent parts being represented by arrows, and when thebrake-operating lever 38 is moved in the direction indicated by thearrow 200 in Figs. 1 and 3 the brake-beam 33 will be carried forwardwith the brakeoperating lever, so as to apply the brakes to the shoes.When the brake-operating lever 38 is moved in the direction indicated bythe arrow 200, the rack-bar 71 will be moved in the direction indicatedby the arrow 201, and if the brake-shoes are not worn the rack-bar 71will slide in its housing, but its teeth will remain in engagement withthe teeth of the dog 83, the teeth of the rack-bar 71 playing back andforth on the teeth of the dog 83 when the brakes are applied andreleased, and this play back and forth of the rack-bar 71 will continueuntil the brake-shoes have been worn sufficiently to permit the teeth ofthe rack-bar 71 to be disengaged from their normally-cooperating teethof the dog 83 and be moved into engagement with the next adjacent toothof the said dog. Let it be supposed that the brake-shoes have becomeworn sufficiently to cause the rack-bar 71 to be engaged with the toothof the dog 83 next adjacent to that tooth with which a tooth of therack-bar is normally in engagement. This engagement of the rack-bar 71takes place on the forward movement of the brakeoperating lever 38,namely, when the brakes are applied, and when the brakes are releasedand the brake-operating lever 38 moves in the direction opposite to thatindicated by the arrow 200 it will be seen that the rack-bar 71 is nolonger free to respond to thismovement, but is held stationary by thebrakebeam, and consequently the connecting-pin of the rack-bar 71, withthe short arm of the lever 38, constitutes the fulcrum for the brake.-operating lever, so that, as the brake-operating lever moves backward onits new fulcrum, the fulcrum-pin 66 will be carried backward toward thebrake-beam an amount substantially equal to the distance of one tooth ofthe rack-bar 71, which represents the amount of wear on the brake-shoes.

By reference to Fig. 3 it will be seen that, when the fulcrum-pin 66moves in the slot of the frame 63 toward the brake-beam 33 on the pinwhich fastens the rack-bar 71 to the said lever as a center, theholding-dogs 67 68 move with the fulcrum-pin 66 and tend to move awayfrom the cam-wheel 69, but by reason of the cam-wheel 69 being connectedby the links 72 73 to the fulcrum-pin movement of the fulcrum-pin towardthe brakebeam produces movement of the cam-wheel 69 on the shaft orarbor as a center, and while the teeth of the cam-wheel remain inengagement with the dogs the said wheel will be turned sufficiently toengage a new tooth or teeth on the wheel with the tooth or teeth ontheholding pawls or cams 67 68, so that the connection between thebrake-operating lever and the brake-beam through the frame 63' is keptpractically rigid and in condition to eifect the movement of thebrakebeam on the movement of the brake-lever in a direction indicated bythe arrow 200. It will thus be seen that on the forward movement of thebrake-lever in the direction indicated by the arrow 200 the rack-bar 71will hold the small or lower arm of the brake-lever when the brake-shoewears, and prevents the return of the lower arm of the brake-lever backto its normal position, but by reason of the original fulcrum 66 of thebrake-lever moving toward the brake-shoe an amount substantially equalto the amount that the small arm of the brake-lever is restrained thesaid brake-lever is in this manner brought into a new position withrelation to the brakebeam, but one in which the angularity' of thebrake-lever with relation to the brake-beam is the same or substantiallythe same as the original or normal angularity of the said lever. As aresult, the power employed to move the brake-lever when the brake-shoesare of normal size and unworn is not expended fruitlessly when thebrake-shoes become worn, but the effect of this power remains the sameeven when the brake-shoes are worn, which result is effected, as abovedescribed, by preserving the normal an gularity of the brake-levers. Asthe live brake-lever 38 is connected to the dead lever 36 by the lowerbrake-rod 40, the effect of the wear upon the shoes carried by thebrake-beam attached to the dead lever will be felt upon the live lever,and will be compensated for at the same time that the wear of the shoesattached to the brake-beam 33 is taken care of.

In Fig. 2 I have shown my invention as applied to a car-truck with thebrake-beams located between the car-wheels, the operation beingsubstantially the same as that described in connection with Fig. 1, thelive lever 60 having connected to it the rack-bar 71 and the housing 82being connected to the frame 63, which is connected to the brakebeam 55,'the fulcrum of the dead lever 58 being in this case movable toward thebrakebeam, but preserving the angularity of the operating-levers.

It is obvious that many minor modifications may be made to adapt myinvention to the many different styles of car-trucks and brakebeams,butin all the modifications or adaptations the mode of operation will besubstantially the same as herein described. It will be observed that thetoothed wheel 69 toall intents and purposes forms a rack-bar, with whichcooperates a pawl or dog carried by the fulcrum of the brake-operatinglever to obtain an adjustable yet rigid connection between theoperating-lever and the brake beam, and the rack-bar 71 and the dog orpawl 83 accomplish the same result of an adjustable yet rigid connectionbetween the brake-beam and the lower arm of the lever, and while I mayprefer this segmental form of rack-bar or toothed cam-wheel 69 I do notdesire to limit my invention in this respect, as this form may bechanged.

I claim- 1. In an automatic brake-slack adjuster, the combination of thefollowing instrumentalities, viz: a brake-beam, a brake-operating leverprovided with a movable fulcrum,

a supporting-frame for the movable fulcrum attached to the brake-beam,means to effect an adjustable yet operatively rigid connection betweenthe brake-beam and the fulcrum of the brake-operating lever, and an adjustable connection attached to the brake-operating lever at one side ofthe movable fulcrum and movable with relation to the brakebeam to takeup the wear of the brake-shoes, means to render the adjustableconnection rigid to the brake-beam when in its adjusted position andthereby effect the movement of the movable fulcrum of thebrake-operating lever, substantially as described.

2. In an automatic brake-slack adjuster, the combination of thefollowing instrumentalities, viz: a brake-beam, a brake-operating leverprovided with a movable fulcrum, a supporting-frame for the movablefulcrum secured to the brake-beam, a pawl movable with the said fulcrum,a rack-bar eooperatin g with the said pawl, a rack-bar attached to thelever on one side of the movable fulcrum, a pawl carried by thebrake-beam and coopcrating with the said rack-bar to connect the latterto the brake-beam, substantially as and for the purpose specified.

3. In an automatic brake-slack adjuster, the combination of thefollowing instrumentalities, viz: a brake-beam, a lever-supporting framesecured to said beam and provided with longitudinally-extended slotssubstantially at right angles to each other, the brakelever extendedthrough one of said slots, a fulcrum for said lever movable in the otherof said slots, araek-bar carried by said frame, a pawl movable with thefulcrum of the said lever and cooperating with said rack-bar, a secondrack-bar operatively connected to said brake-lever, a housing or supportfor the second rack-bar carried by the brakebeam, and a pawl carried bythe brakebeam and cooperating with said second rack-bar, substantiallyas described.

4. In an automatic brake-slack adjuster, the combination of thefollowing instrumentalities, viz: a brake-beam, a lever-supporting frameattached thereto, a brake -lever provided with a fulcrum movable on saidsupporting-frame, a rack-bar carried by the said supporting-frame, apawl movable with the fulcrum of the brake-lever and cooperating withthe said rack-bar, a second rack-bar operatively connected to thebrake-lever and adj ustably connected to the brake-beam, substantiallyas described.

I 5. In an automatic brake-slack adjuster, the combination of thefollowing instrumentalities, Viz: a brake-beam, a lever-supporting frameattached thereto, a brake-lever provided with a fulcrum movable on thesaid supporting-frame, an adjustable connection between the said fulcrumand the said supporting-frame operative 011 the movement of thebrake-lever in one direction, and an adjustable connection between thebrake-lever and the brake-beam and operative on the movement of thelever in the opposite direction, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ALEXANDER PITKETI'ILY.

lVitnesses:

E. FRANK \VooDBUny, GEORGE L. DOLBEARE.

